Reassortment
Reassortment is the mixing of the genetic material of a species into new combinations in different individuals. Several different processes contribute to reassortment, including assortment of chromosomes, and chromosomal crossover.[1] It is particularly used when two similar viruses that are infecting the same cell exchange genetic material. In particular, reassortment occurs among influenza viruses, whose genomes consist of eight distinct segments of RNA. These segments act like mini-chromosomes, and each time a flu virus is assembled, it requires one copy of each segment.
If a single host (a human, a chicken, or other animal) is infected by two different strains of the influenza virus, then it is possible that new assembled viral particles will be created from segments whose origin is mixed, some coming from one strain and some coming from another. The new reassortant strain will share properties of both of its parental lineages.
Reassortment is responsible for some of the major
The reptarenavirus family, responsible for inclusion body disease in snakes, shows a very high degree of genetic diversity due to reassortment of genetic material from multiple strains in the same infected animal.
Multiplicity reactivation
When influenza viruses are inactivated by UV irradiation or ionizing radiation, they remain capable of multiplicity reactivation in infected host cells.[5][6][7] If any of a virus's genome segments is damaged in such a way as to prevent replication or expression of an essential gene, the virus is inviable when it, alone, infects a host cell (single infection). However, when two or more damaged viruses infect the same cell (multiple infection), the infection can often succeed (multiplicity reactivation) due to reassortment of segments, provided that each of the eight genome segments is present in at least one undamaged copy.[8]
See also
- Other kinds of nonhereditary genetic change
References
- ISBN 978-0-8153-2045-6.
- ^ "1968 Pandemic (H3N2 virus)". US Centers for Disease Control and Prevention (CDC). 2019-01-22. Retrieved 2021-01-18.
- PMID 27929449.
- ^ "Deadly new flu virus in US and Mexico may go pandemic". New Scientist. 2009-04-24. Retrieved 2009-04-26.
- PMID 13687359DOI: 10.1016/0042-6822(61)90330-0
- PMID 14888814
- PMID 6066111DOI: 10.1038/2141235a0
- PMID 18295550
- History of April-2009 flu collected by Bionyt.
External links
- An animation from hhmi.org illustrating the process Archived 2005-11-23 at the Wayback Machine
- Hood E (February 2006). "Flu Vaccine Production Gets a Shot in the Arm". Environ Health Perspect. 114 (2): A108–11. PMID 16451835.
- Simon-Loriere, Etienne; Holmes, Edward C. (2011). "Why do RNA viruses recombine?". Nature Reviews Microbiology. 9 (8): 617–626. PMID 21725337. Offers a good introduction with figures on the concept of reassortment (as well as recombination).